Neisseria meningitidis is a Gram-negative encapsulated bacterium that can cause sepsis, meningitis, and death. N. meningitidis can be classified into at least 12 serogroups (including serogroups A, B, C, 29E, H, I, K, L, W-135 (mostly now referred to as W), X, Y and Z) based on chemically and antigenically distinctive polysaccharide capsules. Strains with five of the serogroups (A, B, C, Y, and W135) are responsible for the majority of disease.
Meningococcal meningitis is a devastating disease that can kill children and young adults within hours despite the availability of antibiotics. There is a need for improved immunogenic compositions against meningococcal serogroups A, B, C, Y, and W135 and/or X.
Currently, a cross-protective vaccine or composition effective against a wide range of MnB and meningococcal serogroups A, C, Y, and W and/or X isolates is not yet commercially available. For example, published results-to-date relating to a licensed multi-component composition for protection against serogroup B disease has not demonstrated a direct bactericidal immune response against multiple meningococcal strains that express non-serogroup B capsular polysaccharides, at least in adolescents. Accordingly, a cross-protective vaccine or composition effective against diverse MnB and meningococcal serogroups A, C, Y, and W and/or X isolates is needed as is determining real-world vaccine coverage against a panel of diverse or heterologous meningococcal strains (e.g., representing different geographical regions).
It is a further object of the invention to provide improved schedules for administering a meningococcal vaccine, in particular to children. While incidence rates of invasive meningococcal disease (IMD) vary with age, incidence is often highest during infancy from age 1 month to 1 year, with a second peak in incidence during adolescence. In the United States, during 1998 to 2007, the overall rate of meningococcal disease in infants aged less than 2 years was 3.9 per 100,000. In children aged 2 to 10 years, the incidence was 0.68 per 100,000, with 41% of cases in this age group occurring in children aged 2 to 3 years. National surveillance data from Australia show the peak incidence of disease in children aged 4 years or less, with a secondary peak in adolescents and young adults; approximately 85% of all cases are attributed to serogroup B disease.